As the other review says, this isn't really a gardening book, but gardening advice in the style of famous authors. Which, as long as you know the author's style, is quite funny.
So Machiavelli talks of how a wise Gardener knows it is not prudent to cut back his lawn too harshly, thus stifling growth, nor too infrequently, thus inviting disorder and rebellious tussocks, and there's a moving description on Caring For Heather, once the delight of the seafront amusements, and now sadly confined to a windowsill in a nursing home by Alan Bennett.
I quite liked those. On the other hand, the section on Growing Potatoes with Berthold Brecht didn't really do it for me: a sergeant comes and digs up an old woman's garden so he can get potatoes to feed the army. Hmm.
I suspect this would suit people who are both keen gardeners and amazingly widely read, because if you don't know the style getting copied, it falls rather flat. I'm not certain that's a large market, but I guess it's out there...